ModelicaML Value Bindings for Automated Model Composition

ModelicaML Value Bindings for Automated Model Composition

Wladimir Schamai (EADS Innovation Works, Germany)

Philipp Helle (EADS Innovation Works, Germany)

Peter Fritzson (Linköping University, Sweden)

Chris Paredis (Georgia Institute of Technology, USA)

Table of Contents

• Introduction

• Challenge

• Value Bindings Concept and Example

• Using Value Bindings for Models Composition

• Conclusion


Page 2

Introduction: ModelicaML

• ModelicaML integrates a subset of

the UML and the Modelica language

in order to leverage standardized

graphical notations of UML for

system modeling and the simulation

power of Modelica

• ModelicaML enables engineers to

describe

• System requirements

• System design (structure and

behavior)

• Usage-, test scenarios


Page 3 03/05/2012

• vVDR (Virtual Verification of Designs against Requirements) is a method that enables a

model-based design verification against requirements

• vVDR is supported in ModelicaML

Introduction: vVDR Method

Formalize Requirements

Formalize Designs

Formalize Scenarios

Create Verification Models

Execute and Create Report

Analyze Results


Page 4 03/05/2012

RMM Requirement

Monitor Models

Scenario Models SM

Designs

Alternative Models DAM

VM Verification Models

AUTOMATED

Task Created Artifact

Goal: Enable on-demand

verification of designs

against requirements

using automated model

composition at any time

during development.

AUTOMATED

Actor

Reports

*

Focus of this

presentation


Page 5

Challenge

We want to verify different design alternatives against sets of requirements using

different scenarios. Questions:

1) How to find valid combinations of design alternatives, scenarios and requirements in

order to enable an automated composition of verification models?

2) Having found a valid combination: How to bind all components correctly?

…

Create Verification Models

… RMM

1. Verification

Model VM DAM SM

2. Verification

Model VM …

…

Requirement Models Scenario Models Designs Alternative Models

DAM SM

DAM

DAM SM

SM

SM SM

SM RMM

1

RMM

RMM

RMM

RMM SM

RMM

RMM

RMM

RMM

… …

n. Verification

Model

*


Page 6

Solution Proposal: Value Bindings

• Value Binding enables the automation of

verification model composition

• Value Bindings include the definition of:

– Client (component that requires data from

other components)

– Provider (component that provides data for

other components)

– Mediator (mediates between clients and

providers)

• Depending on which mediators and

providers are in place we can:

• Determine which clients can be satisfied

• Find valid combinations and generate

verification models

• Generate binding code for client

components in verification models

c

p

M

Clients

Mediators

Providers

VM

Verification

Model

RMM

Requirement

Monitor

Models

SM

Scenario

Model

DAM

Design

Alternative

Model

M

c

c

p

c

p

c

p

ORM

Other

Required

Models


Page 7

Example: Design Alternative Model

Simplified Aircraft Potable Water System

- Overhead tank system that

can be filled using a liquid

source from bottom with the

aircraft on ground.

- Controller monitors the

level of liquid and controls

the valves according to its

mode (e.g. “fill”-, “drain”-,

“pre-selected value fill”-

mode).

Liquid in (from liquid source) Liquid out


Page 8

Example: Requirement Monitor Model ”The time to fill an empty tank shall be 300 sec. max.”

“status” is set by the violation monitor and

indicates the following:

0 = not evaluated

1 = evaluated and not violated

2 = violated

Clients to get input values from

design model providers


Page 9

Example: Design Alternative Model

Provider for

requirements

Clients to get

input values

from scenarios


Page 10

Example: Scenario Model “Filling and draining the tank”

Example scenario: Tank cleaning by filling and

draining the tank several times when the aircraft

is on ground.

Providers for design model clients

Action code:

mode := 1; // fill mode

preselectedLevel := 1;

pumpPowerFactor := 1;


Page 11

Example: Mapping Scenarios to Requirements

Engineer (e.g. tester) has to define which scenarios are appropriate to verify which

requirements?

• One scenario can be used to verify multiple requirements (to increase requirements

coverage and confidence in verification results)

• Each requirement should be referenced by at least one scenario

These relations

are defined

manually (could

be automated in

the future)

Verification Model Composition in ModelicaML: Finding Valid Combinations - Goal

• Value Bindings are used to determine valid combinations as follows:

– Select a design alternative

• Find combinations consisting of

– 1 scenario that can stimulate this design model and

– n requirements that are implemented in the design, and can be verified

using this scenario.

• Each combination is used to generate one verification model.


Page 12 03/05/2012

Verification Model Composition in ModelicaML: Finding Valid Combinations - Algorithm


Page 13 03/05/2012

?

Select Design Alternative

Select Scenario

?

Analyze (Next) Scenario

Analyze (Next) Requirement

Select Requirement

Y N

Y N

DAM

RMM

VM

SM

RMM

VM

SM

?

Create Combination

(i.e. Create Verification

Model)

else

More requirements

…

?

…

…

More scenarios

DAM

Clients of design

alternative satisfied

by providers from

scenario?

Requirement is referenced by scenario

and requirement clients satisfied by

providers from design alternative?

?

More req.

else

* Next scenario if no requirement

* Abort if no scenario

Combinations

else


Page 14

Automatic Binding Code Generation in ModelicaML

Value Bindings are used to automatically generate binding code for all clients in the

verification model (i.e. a combination of design model, scenario and a set of requirements):

Example: Binding code for the client tankIsEmpty of the requirement req_001_...:

tankIsEmpty = sm_spws_environment.spws.tank.level < 0.001

Design Model

Scenario Model

Requirement

Models

Verification Model

Binding

Provider from

design model

Client from requirement model


Page 15

Simulation and Report Generation in ModelicaML

Verification models are simulated.

The generated Verification

Report is a prepared summary of:

• Configuration, bindings

• Violations of requirements

• etc.


Page 16

Conclusion

• The ModelicaML Value Bindings approach enables automated model composition, which

is used in ModelicaML for automatic generate verification models

• Bindings do not modify client or provider models (important when libraries are used)

• Using binding definitions we can find valid combinations and generate verification

models

• The binding code can be generated for all client components automatically

• The generated verification models become artifacts that are created automatically on-

demand and do not need to be maintained

Thank you for your attention!

Wladimir Schamai

EADS Innovation Works (Germany)

[email protected]

Peter Fritzson

Linköping University (Sweden)

[email protected]


Page 17

mailto:[email protected]

mailto:[email protected]

ADDITIONAL SLIDES


Page 18 03/05/2012


Page 19

vVDR Method Steps Explanation

1. Formalize Requirements: This step explains how select and formalize requirements for

the design verification purpose.

2. Formalize Designs (Select or Create Design Model to be Verified against

Requirements ): This step clarifies what properties a system design model needs to have

for being suitable for this method.

3. Formalize (Verification) Scenarios: This step describes what the properties of a

verification scenario are.

4. Create Verification Models: This step explains what a verification model consists of.

5. Execute Verification Models and Create Report: This step imposes requirements on

the simulation output.

6. Analyze Results: This step provides guidance for analyzing possible causes of

inconsistencies found in the simulation results.


Page 20

Verification Artifacts Traceability in ModelicaML

The same algorithm for finding valid combination is used to infer the traceability between

requirements, scenarios and design alternatives:

• Requirements view shows which requirements are implemented and can be tested using

which scenarios

• Scenarios view shows scenarios that are appropriate for a design alternative and all

requirements can be verified using this scenario

• For each combination a verification model can be generated on-demand


Page 21

Example of Value Bindings in ModelicaML

With provider operation: “level < 0.001” in order to return a Boolean value.


Page 22

Binding Operations in ModelicaML : Client Operation

• Used when a sub-component client shall be referenced explicitly

• When a value manipulation or type conversion is required

• For overwriting of binding definitions. Any upper binding definition in the components

tree overwrites lower level bindings.


Page 23

Binding Operations in ModelicaML : Mediator Operation

• Built-in functions for taking the minimum or

the maximum value, sum values, build a

product, or to use the logic operators such as

AND, OR, or XOR.

• These functions are only used if multiple

providers are anticipated for this mediator.

• In contrast, the function getSingleProvider()

is used to ensure that there must be only one

provider for this mediator.


Page 24

Binding Operations in ModelicaML : Provider Operation

• Used for type conversion,

• e.g., if client requires a different type compared to the provider type

• Or when the actual provider is a sub-component, e.g.:

• Requirement: When the system is not used (e.g. is not being filled, drained or is not supplying water

to clients) all valves shall be fully closed.

Provider

Provider Operation

with references to

sub-components

Date post:	06-May-2015
Category:	Technology
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